Phenoxybiphenyl and phenoxyterphenyl compounds and compositions

ABSTRACT

Compounds of classes represented by phenoxybiphenyl and terphenyl compounds having from 5 to 10 aromatic rings and from 2 to 8 oxy ether linkages wherein at least 40% of the total linkages are in the meta position, which exhibit liquid properties over a wide range, and compositions containing said liquid compounds together with other fluids representative of which are polyphenyl ethers. These compounds and compositions have many uses, among which are hydraulic fluids and heat transfer fluids.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a division of application Ser. No. 247,528, filed Apr. 26, 1972,and now U.S. Pat. No. 3,860,661, which is a continuation in part of Ser.No. 845,079 filed July 25, 1969, now abandoned which is a continuationin part of Ser. No. 801,875 filed Aug. 19, 1968, now abandoned, which isin turn a division of Ser. No. 310,457 filed Sep. 20, 1963, now U.S.Pat. No. 3,406,207.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to certain new phenoxybiphenyl and terphenylcompounds, to compositions containing phenoxy-biphenyl and terphenylcompounds in admixture with polyphenyl ethers, and to the application ofthese compounds and mixtures as functional fluids.

2. Description of the Prior Art

Many different types of materials are utilized as functional fluids andfunctional fluids are used in many different types of applications. Suchfluids have been used as electronic coolants, diffusion pump fluids,synthetic lubricants, damping fluids, bases for greases, forcetransmission fluids (hydraulic fluids), heat transfer fluids, diecasting release agents in metal extrusion processes and as filtermediums for air conditioning systems. Because of the wide variety ofapplications and the varied conditions under which functional fluids areutilized, the properties desired in a good functional fluid necessarilyvary with the particular application requiring a functional fluid havinga specific class of properties.

Of the foregoing, the use of functional fluids as heat transfer fluidshas posed what is probably the most difficult areas of application.Thus, the requirements of a heat transfer fluid are as follows: Thefluid should be liquid over a wide temperature range, and in generalhave a low vapor pressure so as to be utilized at atmospheric pressure.Such fluid should be operable as a heat transfer media over an extendedperiod of time at given temperatures, and should exhibit a hign-degreeof thermal and hydrolytic stability. Thus, a heat transfer fluid isoften required to operate at temperatures in the order of 700°F. orhigher over extended periods of time. Such fluids, in addition, shouldbe non-corrosive to metals with which they are in contact and inparticular such fluids should be non-corrosive at the required operatingtemperature.

For vacuum pump diffusion oils, the viscosity characteristics of thefluid must be such that it may be used over a wide temperature range;that is, adequately high viscosity at high temperature, low viscosity atlow temperature and a low rate of change of viscosity with temperature.Its volatility should be low at elevated temperatures of use and shouldbe thermally and chemically stable in order to resist oxidation anddecomposition so that it will remain uniform under conditions of use.

SUMMARY OF THE INVENTION

It has now been found that functional fluids which have excellentphysical properties and which are particularly suitable for use as heattransfer fluids are obtained through the use of phenoxybiphenyl and-terphenyl compounds having from 5 to 10 aromatic rings and from 2 to 8oxyether linkages, characterized in that the number of aromatic rings isat least 2 greater than the number of oxyether linkages, and that atleast 40% and preferably at least 50% of the total linkages are in themeta position.

Particularly preferred compositions are those having 6 phenyl rings and4 oxyether linkages, such as 3,4'-bis(m-phenoxyphenoxy)biphenyl. Alsopreferred are mixtures of such di(phenoxyphenoxy)biphenyls wherein atleast 40 percent of the total linkages in the mixture are in the metaposition, such as a mixture of 3,3'- and3,4'-bis(m-phenoxyphenoxy)biphenyl.

The phenoxybiphenyl and -terphenyl compounds either singularly or asmixtures can be blended together with other compounds such asbis(phenoxy)biphenyl compounds, phenoxyphenoxybiphenyl compounds andanalogs thereof as well as polyphenyl ethers and polyphenyl thioethers.

DESCRIPTION OF PREFERRED EMBODIMENTS

The preferred phenoxybiphenyl and -terphenyl compounds of this inventioninclude those compounds randomly constructed of a aromatic rings and boxyether linkages, where a is an integer of from 5 to 10, and b is aninteger determined by the following relationships:

when a is 5 to 7, b = 2 to a - 2

when a is 8 to 10, b = a - 5 to a - 2,

and further characterized in that at least 50% of the total linkages arein the meta position.

The phenoxybiphenyl and -terphenyl compounds as defined in thisinvention have been found to be especially good functional fluidcompositions having high thermal stability, high oxidative stability,high hydrolytic stability, low vapor pressure at elevated temperatures,wide liquid range, good viscosity characteristics, good lubricatingproperties and good metal compatibility when in contact with metalmechanical members of fluid handling systems. The functional fluids ofthis invention are particularly useful as inexpensive high temperatureheat transfer fluids. These fluids are also generally useful as highvacuum diffusion pump oils, dielectric fluids, coolant moderators fornuclear reactors, and as high temperature lubricants and lubricant basestock.

The phenoxybiphenyl and -terphenyl compounds of this invention arecompatible with the lower molecular weight phenoxybiphenyl and-terphenyl compounds having four and less aromatic groups, and with thepolyphenyl ethers, and may be mixed with these compounds to form fluidsfor special end uses. In general, the phenoxybiphenyl and -terphenylcompounds of this invention are present in the mixture compositions in amajor amount by weight, more particularly in a concentration by weightof 60% to 90% or more.

Typical examples of bis(phenoxy)biphenyl compounds which can be blendedwith the phenoxybiphenyl and -terphenyl compounds of this invention are2,3-, 3,3'-, 3,4'-, and 3,4-bis(phenoxy)biphenyls.

Typical examples of polyphenyl ether compounds which can be admixed withthe liquid phenoxybiphenyl and -terphenyl compounds of this inventionare bis(phenoxyphenyl) ethers, e.g., bis(m-phenoxphenyl) ether; thebis(phenoxyphenoxy)benzenes, e.g., m-bis(m-phenoxyphenoxy)benzene,m-bis(p-phenoxyphenoxy)benzene, o-bis(o-phenoxyphenoxy)benzene; thebis(phenoxyphenoxyphenyl) ethers, e.g., bis[m-(m-phenoxyphenoxy)phenyl]ether, bis[p-(p-phenoxyphenoxy)phenyl[ ether, m-(m-phenoxyphenoxy)phenylether, m-(o-phenoxyphenoxy)phenyl ether; and thebis(phenoxyphenoxyphenoxy)benzenes, e.g.,m-bis[m-(m-phenoxyphenoxy)phenoxy]benzene,p-bis-[p-(m-phenoxyphenoxy)phenoxy]benzene,m-bis[m-(p-phenoxyphenoxy)phenoxy]benzene and mixtures thereof withother polyphenyl ethers.

The phenoxybiphenyl and -terphenyl compounds of this invention can beprepared by the reaction of a halogenated benzene, -biphenyl or-terphenyl compound or a halogenated phenoxybenzene, -biphenyl or-terphenyl compound, with a phenolic or a phenoxyphenolic compound suchas an alkali metal salt, especially the potassium salt, of phenol orphenoxyphenol. It is to be understood that the above compositionsbroadly designated as "phenoxy" compounds may contain more than onephenoxy group. Likewise, the above designated halogenated compounds mayinclude more than one halogen atom. For example, halogenatedphenoxybiphenyl is meant to include such compounds as3,4'-dichloro-3'-(m-phenoxy-phenoxy)biphenyl. The reaction in accordancewith this invention is conducted at a temperature range of from about175°C. to about 225°C., preferably from about 175°C. to about 210°C. fora period of time of about 1 to about 16 hours or longer. Said reactionscan be carried out in the presence of a copper catalyst which can bepowdered metallic copper, copper hydroxides, a copper salt such ascuprous chloride, cupric chloride, etc., or mixtures thereof. Whereasthe exact quantity of the copper catalyst is not critical, amounts ofthe order of about 1 to about 6 mole percent of copper, based on thetotal mole equivalence of the halogen groups of the dihalobiphenyl ordihaloterphenyl compound, have been found to be satisfactory. However,it will be understood that smaller and larger amounts of catalysts canbe employed as desired.

After the benzene, biphenyl or terphenyl compound is reacted with thealkali metal phenate at the stated temperatures for from about 1 toabout 12 hours, the reaction mixtures is cooled and poured into a diluteaqueous caustic solution and extracted with a number of portions ofinert solvent, such as benzene, toluene, xylene, carbon tetrachloride,and the like, whereby the aqueous phase removes the alkali halide saltfrom the system. The combined organic phase is then preferably washedwith several portions of dilute potassium hydroxide solutions followedby several washings with water alone, and then the organic phase isdried over a desiccant such as anhydrous magnesium sulfate, filtered,and the organic solvent removed by distillation, whereby thephenoxybiphenyl and terphenyl compounds are retained in the distillationvessel. The reaction product can then be distilled through a Vigreauxcolumn to obtain the phenoxybiphenyl and -terphenyl compounds per se.

It will also be understood that the phenoxybiphenyl and -terphenylcompounds of the instant invention can be treated with active charcoal,attapulgus earth, and/or alumina in a suspended state by mild agitationeither at room or elevated temperature and subsequently filtered. Thephenoxybiphenyl and -terphenyl compounds also can be taken up in anorganic solvent such as benzene, and the organic solution treated withthe aforesaid materials, filtered and the organic solvent removed bydistillation under reduced pressure.

The preferred halogen has been found to be either chloro or bromo withchloro being the most preferred. Thus, it is preferred to use, forexample, a mono- or dichlorobenzene, a mono- or dichlorobiphenyl or-terphenyl as a starting reactant in preparing the compounds of thepresent invention.

Typical examples of biphenyl and terphenyl compounds which can beutilized to prepare the compounds of this invention, particularly thechloro and bromo derivatives thereof are bromo benzene,m-dichlorobenzene, 2,2'-dichlorobiphenyl, 2,3'-dichlorobiphenyl,2,4'-dichlorobiphenyl, 3,3'-dichlorobiphenyl, 2,3-dichlorobiphenyl,2,4-dichlorobiphenyl, 2,5-dichlorobiphenyl, 2-chlorobiphenyl,3-chlorobiphenyl, 4-chlorobiphenyl, 3,3'-dibromo-m-terphenyl,4'-bromo-m-terphenyl, 3'-bromo-m-terphenyl, 3-bromo-m-terphenyl,4-bromo-m-terphenyl, 3'-bromo-o-terphenyl, 4'-bromo-o-terphenyl,3'-bromo-p-terphenyl, 2-bromo-p-terphenyl, 3-bromo-p-terphenyl,3-chloro-3'-phenoxyterphenyl, 4-chloro-3'-(m-phenoxy-phenoxy)terphenyl,3-chloro-3'-[m-(o-phenoxyphenoxy)phenoxy]-m-terphenyl,3-chloro-4'-[m-(m-phenoxyphenoxy)phenoxy]-m-terphenyl,4-chloro-3'-[o-(m-phenoxyphenoxy)phenoxy]-m-terphenyl,2,2'-dichloro-3'-phenoxy-p-terphenyl,2,4'-dichloro-3'-phenoxy-o-terphenyl,2,4'-dichloro-3'-(m-phenoxyphenoxy)-m-terphenyl.

Typical examples of phenolic compounds which can be utilized to preparethe compounds of this invention are phenol, o-phenoxyphenol,m-phenoxyphenol, p-phenoxyphenol, m-(m-phenoxyphenoxy)phenol,o-(m-phenoxyphenoxy)phenol, p-(m-phenoxyphenoxy)phenol,m-(o-phenoxyphenoxy)phenol and m-(p-phenoxy)phenoxyphenol,m-(m-phenoxyphenoxy)phenol, m-phenylphenol, 3-hydroxy-m-terphenyl.

In addition, it is contemplated within the scope of this invention thatmixtures of phenoxybiphenyl and -terphenyl compounds can be prepared aswhen a mixture of chlorinated biphenyl compounds, such as chlorinatedbiphenyl compositions containing about 32% chlorine corresponding to anaverage composition containing 2 atoms of chlorine per molecule ofbiphenyl, is utilized as a starting reactant to be interacted as, forexample, with m-phenoxyphenol. Thus, a mixture of compounds of thisinvention is prepared which is useful in the many applications as setforth above, particularly for use as a heat transfer fluid. In preparingthe mixture of phenoxybiphenyls and -terphenyls, the same processconditions are utilized as used in the preparation of the purecompounds.

The phenoxybiphenyl and -terphenyl compounds of this invention areconveniently referred to as a phenyl b oxyethers, where a is the numberof phenyl groups and b is the number of oxyether linkages. The term"phenyl" as used herein is meant to include mono-, di- and trivalentradicals derived from benzene by abstraction of one, two or threehydrogen atoms; i.e., ##SPC1##

and the term oxyether is meant to designate the --O-- structure. Aspreviously described, the compounds included within the scope of thisinvention are those having from 5 to 10 phenyl groups and from 2 to 8oxyether linkages, but subject to the following relationship, that

when a is 5 to 7, b is 2 to (a - 2), and

when a is 8 to 10, b is (a - 5) to (a - 2), and

further subject to the limitation that at least 40% and preferably 50%of the total linkages are in the meta position.Specific examples of thepreferred a phenyl b oxyether compounds included within the scope ofthis invention are given below to more clearly illustrate the invention.Examples of the preparation of some typical compounds are also provided.The specific compounds mentioned are for illustration only, and the listis not intended to be exhaustive nor to limit the scope of theinvention. The exemplary compounds are given in order of increasingmolecular weight.

1. 5 phenyl 2 oxyether

3,3'-diphenoxy-m-terphenyl

4'-(m-phenoxyphenoxy)-m-terphenyl

2. 5 phenyl 3 oxyether

3-phenoxy-3'-(m-phenoxyphenoxy)biphenyl

3-phenoxy-3'-(o-phenoxyphenoxy)biphenyl

3-phenoxy-4'-(m-phenoxyphenoxy)biphenyl

4-phenoxy-3'-(m-phenoxyphenoxy)biphenyl

3-[m-(m-phenoxyphenoxy)phenoxy]biphenyl

3-[o-(m-phenoxyphenoxy)phenoxy]biphenyl

EXAMPLE I Preparation of 3-Phenoxy-3'-(m-phenoxyphenoxy)biphenyl

A 500 ml. reaction flask equipped with stirrer, condenser and Dean-Starktrap was charged with 250 g. (2.66 moles) of phenol. This was heatedwith stirring at 100°C. while 56 g. (1.0 mole) of potassium hydroxidewas added in increments. Toluene (50 ml.) was then added to the fluldmass and water azeotroped from the system. After all toluene and waterhad been removed, 150 ml. of diglyme was added together with 5.0 g.(0.05 mole) of cuprous chloride and 1.0 g. of copper powder. To thismixture 20 g. (0.053 mole) of 3-chloro-3'-(m-phenoxyphenoxy)biphenyl indiglyme was added over a 30 minute period. Diglyme was distilled fromthe mixture which was then heated at 240° for 18 hrs. On cooling themixture was slurried in 200 ml. of ether and salts were filtered off.The ethereal solution was washed with 25% potassium hydroxide solution,water until neutral and then dried over magnesium sulfate. The ether wasremoved under vacuum and the resulting oil distilled to give 13.1 g. ofthe desired product, bp 248°-253° /0.06 mm., n_(D) ²⁵ 1.6474.

Synthesis of the key intermediate compound3-chloro-3'-(m-phenoxyphenoxy)biphenyl used in the above preparation isdescribed in the procedure of Example III.

Calculated for C₃₀ H₂₂ O₃ : C, 83.7; H, 5.2. Found: C, 83.2; H, 5.2.

3. 6 phenyl 2 oxyether

1-(2,4-diphenylphenoxy)-3-(3-phenylphenoxy)benzene

3-(2,4-diphenylphenoxy)-3'-phenoxybiphenyl

3-(3-phenylphenoxy)-3'-phenoxy-p-terphenyl

4-[m-(m-phenylphenoxy)phenoxy]-m-terphenyl

4. 6 phenyl 3 oxyether

4'-[m-(m-phenoxyphenoxy)phenoxy]-m-terphenyl

4'-[m-(o-phenoxyphenoxy)phenoxy]-m-terphenyl

4'-[m-(p-phenoxyphenoxy)phenoxy]-m-terphenyl

4-[m-(m-phenoxyphenoxy)phenoxy]-m-terphenyl

EXAMPLE II Preparation of 4'-[m-(m-Phenoxyphenoxy)phenoxy]-m-terphenyl

A 500 ml. flask equipped with dropping funnel, stirrer, thermometer, anda Dean-Stark trap surmounted by a Friedrichs condenser, was charged with100 g (0.36 mole) of m-(m-phenoxyphenoxy)phenol and 9.5 g of potassiumhydroxide. The reaction mixture was heated with stirring until thepotassium hydroxide had completely dissolved; then 250 ml. of toluenewas added to azeotrope the theoretical amount of water. Toluene was thendistilled from the system until the temperature reached 200°C. After thetemperature of the reaction mixture had returned to 150°C., 100 ml. ofdiglyme was added, together with 2.5 g. of cuprous chloride and 0.5 g.of copper powder.

The temperature was gradually increased to 160°C. and 20.6 g. (0.067mole) of 4'-bromo-m-terphenyl, dissolved in 40 ml. of diglyme, was addeddropwise. The reaction was allowed to continue for 10 hr. at 185°C. Itwas then diluted with ethyl ether and filtered. The ether layer waswashed with 200 ml. of 25% aqueous potassium hydroxide, followed bywater washing until neutral. The aqueous washes were extracted with 200ml. of ethyl ether, the ether layers combined, washed with distilledwater until neutral, dried over magnesium sulfate, and filtered. A brownviscous liquid was obtained upon removal of the ether. This material wasdistilled to obtain 23.5 g. of4'-[m-(m-phenoxyphenoxy)phenoxy]-m-terphenyl, as a yellow viscousliguid, bp 337°C/0.07 mm. Final purification of this material waseffected as described above in Example I.

Calculated for C₃₆ H₂₆ O₃ : C, 85.2; H, 5.2. Found: C, 85.4; H, 5.2.

Synthesis of the key intermediate 4'-bromo-m-terphenyl used in thepreceeding preparation was according to the following procedure.

A 1 liter flask equipped with a stirrer, thermometer, reflux condenser,and dropping funnel was charged with 300 g. (1.3 moles) of terphenyl and250 ml. of ethylene dichloride. The resulting mixture was heated to80°C., and several ml. of bromine, several grams of freshly cleaned ironfilings, and a few drops of water were added to the reaction mixture. Assoon as bromination started, the reaction mixture was cooled to roomtemperature. A total of 177 g. (1.11 moles) of bromine was added over aperiod of 3 hr. The reaction mixture was cooled in an ice-water bath andfiltered to remove 4'-bromo-p-terphenyl as a red-brown solid. Thefiltrate was concentrated under vacuum and the resulting oil treatedwith a 10% sodium sulfite solution to remove excess bromine, followed bywashing with 5% potassium hydroxide solution. The crude bromide wasdistilled under reduced pressure to give 93.9 g. of4'-bromo-m-terphenyl, bp 200°-204°C./1.9 mm.

5. 6 phenyl 4 oxyether

3,3'-bis(m-phenoxyphenoxy)bipheny

3,3'-bis(p-phenoxyphenoxy)biphenyl

3-(m-phenoxyphenoxy)-3'-(o-phenoxyphenoxy)biphenyl

3-(m-phenoxyphenoxy)-3'-(p-phenoxyphenoxy)biphenyl

3-(p-phenoxyphenoxy)-4'-(m-phenoxyphenoxy)biphenyl

EXAMPLE III Preparation of 3,3'-Bis(m-phenoxyphenoxy)biphenyl

A 500 ml. four-necked flask equipped with stirrer, thermometer, andDean-Stark strap surmounted by a Friedrichs condenser, was charged with93.5 g. (0.505 mole) of m-phenoxyphenol, and 30.8 g. (0.50 mole) ofpotassium hydroxide was added in increments with stirring at 100°C.After the initial exothermic reaction had subsided, 80 ml. of toluenewas added and water azeotroped from the reaction mixture until thetheoretical amount had been collected, including that from the potassiumhydroxide. The toluene was distilled from the reaction mixture until thepot temperature reached 230°C. After cooling to 150°C., 100 ml. ofdiglyme was added together with 7 g. of cuprous chloride and 2 g. ofcopper powder. The reaction mixture was then heated with stirring to170°C. and 129.3 g. (0.57 mole) of 3,3'-dichlorobiphenyl was added overa 1 hr. period. Diglyme was distilled from the reaction mixture untilthe pot temperature reached 235°C. when reaction was continuted for 18hours. On cooling, the reaction mixture was diluted with an equal volumeof ether, and filtered to remove copper and potassium salts. Theethereal solution was washed three times with 150 ml. portions of 20%potassium hydroxide followed by water washing until nuetral. The waterand potassium hydroxide layers were extracted with additional ether, theether solutions combined and dried over anhydrous magnesium sulfate.After filtration, the ether was removed under vacuum and a darkred-brown oil was distilled to yield 71.4 g. of the intermediatecompound 3-chloro-3'-(m-phenoxyphenoxy)biphenyl, bp 220°-222°C/0.04 mm.and 17.2 g. of the desired product, bp 312°C./0.05 mm. Finalpurification of the desired product was effected by dissolving in ethylether, treating with 1.0 g. of activated charcoal, followed byfiltration through filter aid and removal of ethyl ether under vacuum.

Product bp 312°C/0.05 mm; n_(D) ²⁵ 1.6520

Calculated for C₃₆ H₂₆ O₄ : C, 82.7; H, 5.0. Found: C, 82.4; H, 5.2.

EXAMPLE IV Preparation of3-(m-phenoxyphenoxy)-3'-(o-phenoxyphenoxy)biphenyl

A 500 ml. reaction flask equipped with stirrer, condenser, and DeanStark trap was charged with 191 g. (1.03 moles) of o-phenoxyphenol, 50ml. of toluene and 39.5 g. (0.70 mole) of potassium hydroxide. Themixture was heated to reflux and water azeotroped from the system.Diglyme (100 ml.) was then added followed by 20 g. (0.053 mole) of3-chloro-3'-(m-phenoxyphenoxy)biphenyl over a 30 minute period. To thismixture 2.5 g. of cuprous chloride and 0.5 g. of copper powder was addedand after removing the diglyme be distillation, the reaction mixture washeated at 230°-240° for 18 hours. The mixture was cooled, diluted with500 ml. of ether and centrifuged to remove copper and potassium salts.The salts were washed with additional ether, and the ether fractionscombined and washed with 25% potassium hydroxide solution followed bywater washing to neutrality. After drying the ethereal solution overmagnesium sulfate, and removing ether in vacuo, the resulting oil wasdistilled to give 16.9 g of the desired product, bp 255°-260°/0.02 mm.;n_(D) ²⁵ 1.6480.

Calculated for C₃₆ H₂₆ O₄ : C, 82.7; H, 5.0. Found: C, 83.0; H, 5.3.

EXAMPLE V Preparation of3-(m-phenoxyphenoxy)-3'-(p-phenoxyphenoxy)biphenyl

A 250 ml. reaction flask equipped with stirrer, dropping funnel,thermometer, and Dean-Stark trap surmounted by a Friedrichs condenser,was charged with 200 g. (1.07 moles) of p-phenoxyphenol, and 34.9 g.(0.567 mole) of potassium hydroxide was added in increments at 90°C. Tothe resulting melt was added 50 ml. of toluene and the theoreticalamount of water azeotroped from the reaction mixture followed by removalof toluene up to 230°C. On cooling to 150°C., the reaction mixture wasdiluted with 150 ml. of diglyme and 5.0 g. of cuprous chloride and 1.0g. of copper powder was added. Over a 45 min. period, 20 g. (0.054 mole)of 3-chloro-3'-(m-phenoxyphenoxy)-biphenyl in diglyme was added, and thediglyme was removed by distillation. The stirred reaction mixture washeated at 235°C. for 19 hours. On cooling, an equal volume of ether wasadded and this mixture centrifuged to remove salts. The etherealsolution was washed with 25 % potassium hydroxide solution to removeexcess phenol, water until neutral, and then dried over anhydrousmagnesium sulfate. After filtration and concentration to remove ether,the oil obtained was distilled to obtain 17.5 g. of the desired product,bp 297°-302° C./0.05 mm.; n_(D) ²⁵ 1.6500.

Calculated for C₃₆ H₂₆ O₄ : C, 82.7; H, 5.0. Found: C, 82.5; H, 5.1.

6. 7 phenyl 2 oxyether

1-(2,4-diphenylphenoxy)-3-[m-(3-biphenylyl)phenoxy]benzene

3-(2,4-diphenylphenoxy)-3"-phenoxy-m-terphenyl

1-(3-phenylphenoxy)-3'"-phenoxy-m,m'-quaterphenyl

3-(o-phenoxyphenoxy)-m,m',m"-quinquephenyl

3-(2,4-diphenylphenoxy)-4'-phenoxy-p-terphenyl

3-(2,4-diphenylphenoxy)-4"-phenoxy-m-terphenyl

7. phenyl 3 oxyether

3-phenoxy-5'"-(m-phenoxyphenoxy)-m,m'-quaterphenyl

3-[o-(p-phenoxyphenoxy)phenoxy]-m,m'-quaterphenyl

3-o-[m-(o-phenylphenoxy)phenoxy]phenoxy -m-terphenyl

4-o-[m-(p-phenylphenoxy)phenoxy]phenoxy -m-terphenyl

3-[m-(m-biphenylylphenoxy)phenoxy]-m-terphenyl

4-[o-(m-biphenylylphenoxy)phenoxy]-m-terphenyl

8. 7 phenyl 4 oxyether

3-m-[o-(m-phenoxyphenoxy)phenoxy]phenoxy-m-terphenyl

3-[m-(m-phenoxyphenoxy)phenoxy]-3"-phenoxy-m-terphenyl

3-(p-phenoxyphenoxy)-3"-(m-phenoxyphenoxy)-m-terphenyl

3-(m-phenoxyphenoxy)-3"-(o-phenoxyphenoxy)-m-terphenyl

9. 7 phenyl 5 oxyether

3-(m-phenoxyphenoxy)-3'-[o-(m-phenoxyphenoxy)phenoxy]biphenyl

3-phenoxy-3'-m-[m-(m-phenoxyphenoxy)phenoxy]phenoxy biphenyl

3-(o-phenoxyphenoxy)-3'-[m-(m-phenoxyphenoxy)phenoxy]biphenyl

3-(p-phenoxyphenoxy)-3'-[m-(m-phenoxyphenoxy)phenoxy]biphenyl

EXAMPLE VI Preparation of3-(m-phenoxyphenoxy)-3'-[m-(m-phenoxyphenoxy)phenoxy]biphenyl

A 500 ml. reaction flask equipped with stirrer, condenser and Dean-Starktrap was charged with 59.8 g. (0.215 mole) ofm-(m-phenoxyphenoxy)phenol, 50 ml. of toluene and 7.2 g. (0.129 mole) ofpotassium hydroxide. Water was azeotroped from the system and 100 ml. ofdiglyme added followed by dropwise addition of 20 g. (0.053 mole) of3-chloro-3'-(m-phenoxyphenoxy)biphenyl over a 30 min. period. To thismixture 2.5 g. of cuprous chloride and 0.5 g. of copper powder wasadded. Diglyme was distilled from the system and the resulting mixtureheated at 230°-240°C. for 18 hours. At the end of this time, 250 ml. ofether was added to the cooled mixture and the resulting slurrycentrifuged to remove salts. The ethereal solution was washed thoroughlywith aqueous base, water and then dried over anhydrous magnesiumsulfate. The ether was removed under vacuum, and the resulting oil wasdistilled to give 24.4 g. of the desired product, bp 340°/ 0.05 mm.,n_(D) ²⁵ 1.6510.

Calculated for C₄₂ H₃₀ O₅ : C, 82.0; H, 4.9. Found: C, 81.8; H, 5.0.

10. 8 phenyl 3 oxyether

3-[m-(m-phenoxyphenoxy)phenoxy]-m,m',m"-quinquephenyl

3-phenoxy-3'-(m-phenoxyphenoxy)-m,m',m"-quinquephenyl

bis m-[m-(o-phenylphenoxy)phenyl]phenyl ether

3-{m-[m-(p-phenylphenoxy)phenoxy]phenoxy}-m,m'-quaterphenyl

3-m-{m-[o-(m-phenylphenoxy)phenyl]phenoxy}phenoxy-p-terphenyl

4'-{m- m-[p-(m-phenylphenoxy)phenyl]phenoxy phenoxy}-p-terphenyl

4-{o- m-[o-(m-phenylphenoxy)phenyl]phenoxy phenoxy}-m-terphenyl

11. 8 phenyl 4 oxyether

3-{m-[o-(m-phenoxyphenoxy)phenoxy]phenoxy}-m,m'-quaterphenyl

3-[m-(o-phenoxyphenoxy)phenoxy]-3'-phenoxy-m,m'-quaterphenyl

3-[m-(p-phenoxyphenoxy)phenoxy]-3'-[m-(m-phenylphenyl)-phenoxy]biphenyl

3-{m- m- o-[m-(o-phenylphenoxy)phenyl]phenyloxy phenoxy phenoxy}biphenyl

4'-{m- o-[m-(o-phenylphenoxy)phenoxy]phenoxy phenoxy}m-terphenyl

4-{m- p-[m-(p-phenylphenoxy)phenoxy]phenoxy phenoxy}-m-terphenyl

12. 8 phenyl 5 oxyether

3-[m-(o-phenoxyphenoxy)phenoxy]-3'-[m-(o-phenylphenoxy)-phenoxy]biphenyl

3-[o-(o-phenoxyphenoxy)phenoxy]-3"-(m-phenoxyphenoxy)-m-terphenyl

4-[p-(m-phenoxyphenoxy)phenoxy]-4'-[p-(m-phenoxyphenoxy)phenoxy]biphenyl

3-]m-(o-phenoxyphenoxy)phenoxy]-4'-(m-phenoxyphenoxy)-m-terphenyl

13. 8 phenyl 6 oxyether

3,3'-bis[m-(m-phenoxphenoxy)phenoxy]biphenyl

4,4'-bis[m-(o-phenoxyphenoxy)phenoxy]biphenyl

1-[m-(p-phenoxyphenoxy)phenoxy]-3-m-[m-(p-phenylphenoxy)phenoxy]phenoxybenzene

1-[o-(m-phenoxyphenoxy)phenoxy]-3-{m-[o-(m-phenylphenoxy)phenoxy]phenoxy}benzene

EXAMPLE VII 3,3'-Bis[m-(m-phenoxyphenoxy)phenoxy]biphenyl

A 250 ml. four-necked flask, equipped with stirrer, dropping funnel,thermometer, and Dean-Stark trap surmounted by a Friedrichs condenserwas charged with 59.8 g. (0.215 mole) of m-(m-phenoxyphenoxy)phenol towhich 13.0 g. 0.208 mole) of potassium hydroxide was added at 90°C.followed by addition of 50 ml. of toluene. The stirred reaction mixturewas heated to azeotrope water, followed by distillation of toluene untilthe temperature of the reaction mixture reached 230°C. To this mixtureafter cooling was added 50 ml. of diglyme, 2.5 g. of cuprous chloride,0.5 g. of copper powder, and 20 g. (0.09 mole) of 3,3'-dichlorobiphenylover a 30 min. period at 175 C. Diglyme was distilled from the reactionmixture which was then heated at 230°-260°C. for 18 hr. The cooled verythick semi-solid mass resulting was dissolved in 500 ml. of ethyl etherand the suspended salts removed by centrifugation. The resultingethereal solution was washed thoroughly with 10% potassium hydroxidesolution and with water until neutral, and finally dried over anhydrousmagnesium sulfate. After concentrating this solution, it was distilledusing a 25 ml. still pot attached to a Claisen head and fraction cutter.Distillation using a Wood's metal bath on the still pot gave 10 g. ofviscous red-orange liquid, bp 348°-352°C/0.09 mm. at a pot temperatureof 428°C. Elemental analysis showed this cut to be about 80% of thedesired product and 20%3-chloro-3'-[m-(m-phenoxyphenoxy)phenoxy]biphenyl. The pot residue wasdissolved in 300 ml. of ethyl ether, treated with 1 g. of activatedcharcoal and filtered through filter aid. The ether was removed undervacuum to yield a light orange product, bp 380°-390°C/0.05 mm., n_(D) ²⁵1.658.

Calculated for C₄₈ H₃₄ O_(6:) C, 81.5; H, 4.9. Found: C, 81.6; H, 5.0.

14. 9 phenyl 4 oxyether

3-[m-(m-phenoxyphenoxy)phenoxy]-3""-(m-phenoxy)-m,p,m'-quinquephenyl

3,3""-bis-(m-phenoxyphenoxy)-m,m',p"-quinquephenyl

3-[m-(m-phenoxyphenoxy)phenoxy]-3'"-(m-phenylphenoxy)-m,o'-quaterphenyl

3-[m-(m-phenoxyphenoxy)phenoxy]-3"-m-(3-biphenylylphenoxy)-m-terphenyl

1,3-bis m-[o-(m-phenylphenyl)phenoxy]phenoxy benzene

3-{m- o- m- o-[m-(o-phenylphenoxy)phenyl]phenoxy phenyl phenoxyphenoxy}biphenyl

4-{m- m- m- o-[m-(o-phenylphenoxy)phenyl]phenoxy phenyl phenoxyphenoxy}biphenyl

15. 9 phenyl 5 oxyether

3-[m-(m-phenoxyphenoxy)phenoxy]-3'"-(m-phenoxyphenoxy)-m,m'-quaterphenyl

3-{m-[m-(m-phenoxyphenoxy)phenoxy]phenoxy}-3-(m-phenoxy)-m,m'-quaterphenyl

3-{m-[m-(m-phenoxyphenoxy)phenoxy]phenoxy}-3-(o-phenoxy)-m,m'-quaterphenyl

3-{m[m-(m-phenoxyphenoxy)phenoxy]phenoxy}-3-(p-phenoxy)-m,m'-quaterphenyl

3-{m- m- p-[m-(o-phenylphenyl)phenoxy]phenoxy phenoxy-phenoxy}-m-terphenyl

4-}m- o- m-[m-(o-phenylphenyl)phenoxy]phenoxy phenoxy-phenoxy}-m-terphenyl

4-{m- o- p-[m-(m-phenylphenyl)phenoxy]phenoxy phenoxy-phenoxy}-m-terphenyl

16. 9 phenyl 6 oxyether

3,3"-bis[m-phenoxyphenoxy)phenoxy]-m-terphenyl

3-{m-[o-(o-phenoxyphenoxy)phenoxy]phenoxy}-3"-(m-phenoxyphenoxy)-m-terphenyl

4,4'-bis[m-(o-phenoxyphenoxy)phenoxy]-m-terphenyl

4,4"-bis[m-(m-phenoxyphenoxy)phenoxy]-p-terphenyl

EXAMPLE VIII 4,4'-Bis[m-(m-phenoxyphenoxy)phenoxy]-m-terphenyl

Following the general procedure described in Example VII,4,4'-bis[m-(m-phenoxyphenoxy)phenoxy]-m-terphenyl is prepared bysubstituting 27 g. (0.09 mole) 4,4'-dichloroterphenyl for the3,3'-dichlorobiphenyl of Example VII as the co-reactant withm-(m-phenoxyphenoxy)phenol. The desired product is recovered andpurified substantially as described.

17. 9 phenyl 7 oxyether

3-[m-(m-phenoxyphenoxy)phenoxy]-3'-m-[o-(o-phenoxyphenoxy)phenoxy]phenoxybiphenyl

4-[m-(m-phenoxyphenoxy)phenoxy]-4'-p-[m-(o-phenoxyphenoxy)phenoxy]phenoxybiphenyl

1-{m-[o-(m-phenoxyphenoxy)phenoxy]phenoxy-3-m-[o-(o-phenylphenoxy)phenoxy]phenoxy}benzene

1-{m-[p-(p-phenoxyphenoxy)phenoxy]phenoxy}-3{m-[m-(p-phenylphenoxy)phenoxy]phenoxy}-benzene

18. 10 phenyl 5 oxyether

3-[m-(m-phenoxyphenoxy)phenoxy]-3"-[m-(m-phenylphenyl)phenoxy]-m,m'-quaterphenyl

1,3-bis m-[m-(m-phenylphenyl)phenoxy]phenoxy biphenyl

3-{m- m- m- m-[m-(m-phenylphenoxy)phenyl]phenoxy phenyl -phenoxyphenoxy}-m-terphenyl

4-{m- o- o- m-[m-(p-phenylphenoxy)phenyl]phenoxy phenyl -phenoxyphenoxy}-m-terphenyl

EXAMPLE IX 3,3'-Bis m-[m-(m-phenoxyphenoxy)phenoxy]phenoxy biphenyl

Following the general procedure described in Example VII, 3,3'-bism-[m-(m-phenoxyphenoxy)phenoxy]phenoxy biphenyl is prepared bysubstituting 69 g. (0.215 moles) ofm-[m-(m-phenoxyphenoxy)phenoxy]phenol for the m-(m-phenoxyphenoxy)phenolof Example VII as the co-reactant with 3,3'-dichlorobiphenyl, thedesired product is recovered and purified substantially as described.

The following example illustrates the preparation of mixtures ofx,x'-bis(m-phenoxyphenoxy)biphenyls which are also included within thescope of the present invention.

EXAMPLE X

A sample of chlorinated biphenyl containing 32 percent chlorine, i.e.,about 2 chlorine atoms per biphenyl molecule, was introduced into areaction vessel and isomerized at about 180°C. for about 2 hours with 10weight percent of anhydrous aluminum chloride catalyst to convert4,4'-dichlorodiphenyl isomers into primarily the 3,3'- and 3,4'-isomers.The mixture was cooled, degassed of HCl, and neutralized with sodiumbicarbonate. The resulting mixture was distilled, and distillatecollected over the range of 100°C. to 180°C. at 0.35 mm. of mercury wasrecovered as the desired isomerized product.

To a reaction vessel similar to that described in Example I was added186 organic g. of m-phenoxyphenol (1 mole), 42 g. of potassium hydroxide(0.75 mole) and 50 ml. of toluene. After all of the water had beendistilled off, the reaction mixture containing the potassiumm-phenoxphenate was heated to 170°C. to remove all traces of toluene.Then 5 g. of cupric chloride was added to the reaction mixture and 24.3g. of isomerized dichlorobiphenyl (0.109 mole) added thereto over a 0.5hour period. This reaction mixture was heated at 200° to 210°C. for 16hours with stirring, cooled, the still warm reaction mixture taken up inexcess 3N potassium hydroxide and benzene, filtered through Hy Flo SuperCel, the aqueous phase removed, the organic phase washed with additionalpotassium hydroxide solution, the aqueous phase removed, and the orgaicphase dried over anhydrous magnesium sulfate. The benzene was thenremoved under reduced pressure and the reaction mixture distilled undervacuum and the x,x'-bis(m-phenoxyphenoxy)biphenyl composition boilingover the range of 260° to 305°C. at 0.1 mm. of mercury recovered. Theproduct was redistilled and the fraction boiling from 295° to 300°C. at0.1 to 0.2 mm. of mercury recovered. The recovered composition waswarmed and filtered through a filter bed consisting of attapulgus clayand alumina.

Calculated for C₃₆ H₂₆ O₄ : C, 82.73; H, 5.01. Found: C, 82.54, 82.74;H, 5.13, 5.20.

The x,x'-bis(m-phenoxyphenoxy)biphenyl composition consists essentiallyof the 3,3'- and 3,4'-isomers, and was observed to be a clear, viscousfluid at room temperature having a thermal decomposition point of about837°F. and a boiling point of about 1038°F.

The phenoxybiphenyl and -terphenyl compounds encompassed by thisinvention are useful as hydraulic and heat transfer fluids anddemonstrate a high degree of thermal stability even at temperaturesexceeding 600°F. Test data showing the thermal stability and theviscosity of the fluids prepared in Examples I to VII are given in thetable below.

    ______________________________________                                                           Viscosity, cs.                                             Compound  Thermal Stability                                                                            210°F.                                                                           400°F.                              ______________________________________                                        Ex. I     799°F.  18.9      2.3                                        Ex. II    776°F.  98.7      3.8                                        Ex. III   822°F.  39.6      3.3                                        Ex. IV    775°F.  46.1      3.3                                        Ex. V     819°F.  40.8      3.5                                        Ex. VI    828°F.  64.3      4.5                                        Ex. VII   806°F.  205.7     7.3                                        ______________________________________                                    

The thermal stability was determined as the temperature at which thedecomposition of the compound produced a pressure rise of 0.014 mm.Hg./sec. according to the procedure described in Chemical andEngineering Data, Vol. 6, No. 1, page 89.

The preceding examples are intended to illustrate several embodiments ofthe instant invention. The scope and limits of the invention are definedby the appended claims.

The embodiments of this invention in which an exclusive property or
 1. Afunctional fluid composition consisting essentially of a mixture ofx,x'di(phenoxyphenoxy)biphenyls wherein at least 40 percent of the total2. A functional fluid consisting essentially of a mixture of 3,3'- and3,4'- bis (m-phenoxyphenoxy)biphenyl.